Device for removing injection moulded parts

ABSTRACT

The invention relates to a device for removing injection moulded parts from the mould of an injection moulding machine, especially for plastics, provided with a moveable and a fixed tool mounting plate. The inventive device comprises a drive unit which enables an actuating unit connected to a spindle ( 21 ) to be moved both towards and away from the mould in a linear manner. An engaging element ( 40 ) is also provided to enable the spindle ( 21 ) to be displaced axially. The invention is characterized in that a toothed disk ( 22 ) is secured to one end of the spindle ( 21 ), whereby the diameter thereof (D) is greater than the outer diameter (d) of the spindle ( 21 ). The invention is further characterized in that the toothed disk ( 22 ) corresponds to a tubular component ( 31 ) which can be driven by the drive unit ( 61 ) and which surrounds the spindle ( 21 ) in a free moving manner. The invention is also characterized in that the engaging element ( 40 ) is connected to the moveable tool plate ( 11 ).

DESCRIPTION

[0001] The invention relates to a device for the removal of injection moldings from the mold of an injection molding machine having a movable and a fixed die chucking plate, in particular for plastics, with a drive unit by means of which an actuating element is capable of being moved linearly toward the mold and away from the latter.

[0002] EP 0 724 944 discloses an ejector unit, in which a servomotor, which is fastened to the movable die chucking plate, has a stator and a rotor, the rotor having fastened to it a hollow shaft possessing a ball-screw spindle nut, through which a ball-screw spindle shaft is capable of being moved forward and backward.

[0003] GB 297 22 964 discloses an ejector unit for an injection molding machine, in which the spindle is connected rigidly to the ejector plate and carries a nut which is rotatable via an electric motor.

[0004] In the above-mentioned ejector units, limits are placed in a disadvantageous way on the configuration of the ball-screw spindle nut, since the latter, together with the hollow shaft, is to be as small as possible in terms of its outside diameter.

[0005] DE 42 28 140 A1 discloses an ejector unit, in which an electric motor is seated as an ejector drive on a base capable of being attached to the mold carrier plate, said electric motor being in constant adjusting connection with a plurality of rotationally driveable threaded spindles, an ejector plate being capable of being adjusted on the threaded spindles via nut threads, the ejector plate carrying an ejector ram passing through the base and the mold carrier plate.

[0006] This design has the disadvantage that a large amount of space is required due to the arrangement of the electric motor and of the gear device.

[0007] EP 0 853 537 B1 discloses a device for the treatment and/or removal of injection moldings on an injection molding machine for the processing of plasticizable materials, the drive unit of which is a hollow-shaft motor receiving at least partially within it the actuating element, the device being supported on the mold closing device at a support element.

[0008] Provided centrally in relation to the injection axis of the injection molding machine is a space for arranging an ejector, a core extractor or an unscrewing mechanism, that is to say a device for the treatment and/or removal of injection moldings.

[0009] Due to the arrangement of the support element, the proposed ejector device requires a relatively large space, thus leading to obstructions on the closing side of the injection molding machine.

[0010] With a knowledge of the above-mentioned prior art, the invention pursues the aim of providing a device for the removal of injection moldings from an injection molding machine, in particular for plastics, which, along with a structurally simple, but at the same time robust design, and having a low construction volume, removes the injection moldings from the mold of an injection molding machine reliably.

[0011] The invention achieves this aim by means of the features of claim 1. The following claims are advantageous developments of the invention.

[0012] According to the invention, the ejection rods for removing the injection moldings from the mold of an injection molding machine are connected to a spindle, to which a toothed disk is fastened. This toothed disk is matched with a tubular component which envelops it and by means of which the toothed disk and consequently the spindle can be rotated radially, while at the same time having unimpeded axial movability. The spindle is connected to an engagement component which is designed as a spindle nut or has individual movable sliding elements and for which any desired construction space is available. Thus, in particular, the nut can be designed generously in terms of its strength, since there is virtually no limit to its outside diameter. Furthermore, in the dimensionally appropriate form of construction proposed here, a particularly low level of noise is to be expected.

[0013] In this case, the nut may be arranged in the housing, together with the driveable tubular component, but, in an advantageous arrangement, it may also be installed in the movable die chucking plate. In the last-mentioned version, a particularly short form of construction of the ejector device is implemented, since only the electrical drive, whether it takes the form of an electric hollow-shaft motor or of an electric drive motor driven via gearwheels, is arranged on the outside of the movable die chucking plate.

[0014] In a further advantageous embodiment, the engagement component, the tubular component and the drive unit are combined as a compact structural unit which is fastened releasably to the movable die chucking plate.

[0015] When the gearwheel is arranged on the side facing the movable die chucking plate, the outwardly projecting spindle is surrounded by the drive motor and the housing enveloping the spindle nut, or a concertina is provided, the mouth of which is covered by a cover which is mounted rotatably on the end face of the spindle. When a concertina is used, it is always only the smallest possible construction space which is occupied.

[0016] When a plurality of ejection rods are used, these are connected to one another via a crossmember, a thrust bearing being arranged between the end face of the spindle and the crossmember.

[0017] An example of the invention is presented in the accompanying drawing, in which:

[0018]FIG. 1 shows a structural unit with a hollow-shaft motor in a rotor/nut arrangement,

[0019]FIG. 2 shows a structural unit with a hollow-shaft motor in a nut/rotor arrangement,

[0020]FIG. 3 shows a hollow-shaft motor with a spindle having different pitches,

[0021]FIG. 4 shows a drive of the sleeve via compact motors and a concertina as spindle protection.

[0022] The individual figures illustrate diagrammatically a movable die chucking plate 11 which, when only one ejection rod 24 is used, has a bore 13.

[0023] Furthermore, all the figures illustrate a spindle 21 in which a toothed disk 22 is fastened to one end face. The toothed disk 22 in this case has an outside diameter D which is larger than the outside diameter d of the spindle 22 (see FIG. 2).

[0024] The spindle is matched with an engagement component 40 which either is designed as a spindle nut 41 or is constructed from sliding elements 42.

[0025] The teeth of the toothed disk 22 are matched with an internal toothing of the tubular component 31. The toothed disk 22 is in this case freely movable laterally and forcibly rotatable radially.

[0026] The tubular component 31 is in this case connected either to a rotor 32 of a hollow-shaft motor 43 or, via a toothing 33, to the output gearwheel of an electric drive motor 62.

[0027] The drive unit is in each case enveloped by a housing 51.

[0028] In FIG. 1, a hollow-shaft motor is provided which is arranged in that region of the ejector device which is inclined toward the movable die chucking plate. The spindle nut 41 is provided in the same housing 51 which envelops the hollow-shaft motor 63.

[0029] The free projecting end of the spindle 21 is likewise enveloped by the housing 51.

[0030] In this form of construction, the largest diameter of the ejection unit is arranged in the vicinity of the outside of the die chucking plate 11, so that the components having only a smaller diameter project into the free space in a space-saving manner.

[0031] In FIG. 2, the hollow-shaft motor 63 and the spindle nut 21 are enveloped as a structural unit by a housing 51, the spindle nut 21 being inclined toward the movable die chucking plate 11.

[0032] In the present configuration, part of the spindle 21 projects into an orifice 14 provided in the movable die chucking plate 11. This orifice 14 is connected to two bores 13 through which the ejection rods 24, 25 can be led. The ejection rods 24 and 25 are connected to one another via a crossmember 26. A thrust bearing 27 is arranged between the crossmember 26 and the spindle 21.

[0033] In FIG. 3, the engagement component 40 is arranged in the movable die chucking plate 11. In the present case, the engagement component 40 has a plurality of sliding elements 42 which are matched with the spindle 21. The sliding elements 42 are in this case mounted so as to be angularly movable, so that a spindle 21 possessing a variable pitch can be used.

[0034] In the present configuration of the ejection device, only the drive, designed here as a hollow-shaft motor 63, including the rotor 32 and the tubular component 31, surrounded by the housing 51, is arranged outside the movable die chucking plate 11. This results in an extremely compact and space-saving unit.

[0035] In FIG. 4, the tubular component 31 is driven by an electric drive motor 62. The use of a belt is not illustrated.

[0036] In the present case, that part of the spindle 21 which projects from the spindle nut 41 is enveloped by a concertina 52. The bottom of the concertina 52 is covered by a bottom plate 53 which, rotatably mounted, is fastened to the spindle 21. In this way, the free space is occupied only whenever the spindle actually projects into this space.

[0037] List of References

[0038] Injection molding machine

[0039]11 Movable die chucking plate

[0040]12 Fixed die chucking plate

[0041]13 Bore

[0042]14 Orifice

[0043] Ejection

[0044]21 Spindle

[0045]22 Toothed disk

[0046]24, 25 Ejection rod

[0047]26 Crossmember

[0048]27 Thrust bearing

[0049] Drive

[0050]31 Tubular component

[0051]32 Rotor

[0052]33 Toothing

[0053] (34) Belt

[0054] Engagement component

[0055]40 Engagement component

[0056]41 Spindle nut

[0057]42 Sliding element

[0058] Protection

[0059]51 Housing

[0060]52 Concertina

[0061]53 Bottom plate

[0062] Motor

[0063]61 Drive unit

[0064]62 Electric drive motor

[0065]63 Hollow-shaft motor

[0066] D Diameter of toothed disk

[0067] d Diameter of spindle 

1. A device for the removal of injection moldings from the mold of an injection molding machine having a movable and a fixed die chucking plate, in particular for plastics, with a drive unit by means of which an actuating element, which is connected to a spindle (21), is capable of being moved linearly toward the mold and away from the latter, an engagement component (40) being provided, by means of which the spindle (21) is capable of being moved axially, wherein one end of the spindle (21) has fastened to it a toothed disk (22), the diameter (D) of which projects beyond the outside diameter (d) of the spindle (21), wherein the toothed disk (22) is matched with a tubular component (31) which, enveloping the spindle (21) freely movably, is capable of being driven by the drive unit (61), and wherein the engagement component (40) is connected to the movable die chucking plate (11).
 2. The device as claimed in claim 1, wherein the engagement component (40) is a spindle nut (41).
 3. The device as claimed in claim 1, wherein the engagement component (40) has sliding elements (42), by means of which a spindle (21) having a differing pitch is capable of being moved axially.
 4. The device as claimed in claims 2 or 3, wherein the engagement component (40) is fastened directly to the movable die chucking plate (11).
 5. The device as claimed in claim 1, wherein the tubular component (31) is connected to the rotor (32) of a hollow-shaft motor (63).
 6. The device as claimed in claim 1, wherein a toothing (33), which is connected to a preferably electric drive motor (62), is provided on the outside of the tubular component (31).
 7. The device as claimed in claim 1, wherein the tubular component (31) is capable of being set in rotation via a belt.
 8. The device as claimed in one of claims 5 to 7, wherein the tubular component (31) is mounted directly on the movable die chucking plate (11).
 9. The device as claimed in one of the aforesaid claims, wherein the engagement component (40), the tubular component (31) and the drive unit (41), enveloped by a common housing (51), are a structural unit fastened releasably to the movable die chucking plate (11).
 10. The device as claimed in at least one of claims 1 to 9, wherein, when a plurality of ejection rods (24, 25) connected via a crossmember (26) are used, a thrust bearing (27) is provided between the crossmember (26) and the end face of the spindle (21).
 11. The device as claimed in at least one of the aforesaid claims, wherein that side of the spindle (21) which is opposite the movable die chucking plate (11) is capable of being enveloped by a concertina (52). 